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Forum: General Discussion

Topic: how to use the precompute stems feature on slow laptops - Page: 1

In view of the popular demand, we just implemented in the latest version, the possibility to pre-compute the stem separation and save in a file on disk.
(obviously, for copyright reasons, this is not available for songs that are streamed from idjpool/deezer/soundcloud/beatcould/beatsource/etc)

To use this, you can right-click on any song or group of song, and select "Precompute stems".
When later on you'll load this track on a deck, it will then instantly have the stem separation and will not use any CPU or GPU resources.

(you also have an option in performances, called "precomputeStems", that lets you decide to either always generate precomputed files for all the songs that you load, or to opt to never do on-the-fly stem analysis and only rely on precomputed files)

Let us know in this thread what you think of this feature, if you would use it, and why.

Posted Tue 23 Jun 20 @ 3:49 pm
And to answer the question before it gets asked: the format that VirtualDJ uses to save the files on disk, is not the exact same as the stem format from native instruments.
There are 2 reasons why we decided in the end not to use the existing format:
1) NI stem files only have 4 stems, while VDJ stems have 5 stems, including hihat and kicks.
2) NI stem files are supposed to be made by producers, who want to spread their tracks, so the format includes the original track so that it's "all-in-one" in one single file.
By opposite, VDJ stem files are "companion" files that are supposed to complement an existing library, and we did not want to try to decompress/recompress your original track into a different compression, loosing quality in the process. This goes even more if you're using video files.
By keeping our stem files with only the stems inside, they stay smaller, and your original track stays unmodified, keeping its audio and/or video at the original quality.

That being said, our .vdjstems files are just open multi-track mp4, so if you rename the file from .vdjstems to .vdjstems.mp4, you would be able to import it in any audio software, same as you would any stem file you would get from other stem utilities (with the convenience of doing it locally with virtualdj, and for free ;)

Posted Tue 23 Jun 20 @ 3:53 pm
so this would be like reanalyzing each song in your library, it sounds good if it can take down the usage of the cpu

Posted Tue 23 Jun 20 @ 4:18 pm
Nice work Atomix

Posted Tue 23 Jun 20 @ 4:50 pm
proartPRO InfinityMember since 2008
I have about 5.000 Songs with sycronised Lyrics (.LRC). So thats really good for "instant karaoke" or or to sing along without vocals of the song.
I am very excited about this new opportunity to preanalyze stems with an Nvidia-GPU and play it on a computer without an supported GPU.


Posted Tue 23 Jun 20 @ 5:26 pm
So, could this mean if i update my 6 year old laptop to windows 10 and precompute my tracks will 2021 then work for me, curently 4th gen i7 with nvidia gt 470 gpu, i know it will be slow but this would be one time only

Posted Tue 23 Jun 20 @ 5:50 pm
yes, that's what it means

Posted Tue 23 Jun 20 @ 5:55 pm
Awesome, saves me the cost of new laptop, just one more question how big are the files produced by the stems on average9 just want to make sure i have room on my hard drive

Posted Tue 23 Jun 20 @ 6:00 pm
stalkker wrote :
Awesome, saves me the cost of new laptop, just one more question how big are the files produced by the stems on average9 just want to make sure i have room on my hard drive

about 2 to 3 times the size of the original mp3

Posted Tue 23 Jun 20 @ 6:09 pm
Ouch i`d better not precompute too many tracks then, thanks stephane

Posted Tue 23 Jun 20 @ 6:17 pm
Things must've improved, because a few days ago they were saying it was 5 or 6 times the file size.

Posted Tue 23 Jun 20 @ 6:29 pm
ok playing around with the new build 5949 and with the new precompute stem it takes hella time to do, I might as well buy a new Computer. I hope this get better because i'm feeling the new stem feature.

Posted Tue 23 Jun 20 @ 10:07 pm
The precompute uses exactly the same process as the 'on-the-fly'. It won't be any quicker.

The advantage is you can compute them prior to going to a gig and thus reduce the strain on your machine whilst performing.

It doesn't change the fact that a modern PC/Mac with a good graphics card is going to be significantly beneficial.

Posted Tue 23 Jun 20 @ 10:23 pm
NicotuxHome userMember since 2014
pre-analyze at load taking 20% of track duration and 100%cpu
saved pre-analyze takes 500% of track storage
load of pre-analyzed takes 500% of simple track load

would it not be fine to test a compromize : load track and analyze just in time taking 20% extra CPU load all track duration and no extra storage ?
as VDJ mostly use 20% of most CPU this may a viable solution, making updated filters to be used at update

Posted Tue 23 Jun 20 @ 10:24 pm
Where are the pre analyzed tracks stored ?

Posted Wed 24 Jun 20 @ 9:47 pm
They're in the same directory as the file they were made from.

Posted Wed 24 Jun 20 @ 9:52 pm
figured it out : same folders as the original file .... is there a way to place them in a separate designated folder ? That way I can have some control over the space used by the stems files . By the way : this manual precompute stems is the prefect solution for my older laptops !

Posted Wed 24 Jun 20 @ 10:09 pm
No you can't move them as they are linked to the main file.

If you move them then VDJ won't know where to find the file. The .vdjstems file must stay in the same folder as the original track.

Posted Wed 24 Jun 20 @ 10:37 pm
LIMOLPRO InfinityMember since 2003
You realize when you right click on a title => precompute stems the number of seconds and minutes it takes to scan the title and create the VDJStems file.

In addition the vdjstems file is 4 times the size of the mp3 file
It's really heavy, you will have to buy a big hard drive.
personally I don't need to scan titles to create vdjstems files


Posted Wed 24 Jun 20 @ 11:19 pm
Thank you...thank you.....thank you.
Any added functionality of the feature will be the icing on the cake...
Like right-clicking the song position wave display and the option to compute stem/save stem that's on the deck. Or could that be done with a custom button? It makes it even more functional, but as I said, this is just icing.
But even if not...Thank You, Thank you, Thank you....
Edit... Actual for the deck options can be added to stems pad page.
I don't mean to get on your nerves... My wheels just be turning...turning...and turning

Posted Thu 25 Jun 20 @ 4:53 pm